Air monitoring can anticipate possible changes in ecosystems

Published: Thursday, June 26, 2008, 16:06 [IST]

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Washington, June 26 : A new research has determined that when rain settles the atmosphere and brings air pollutants to the ground, it can have a lasting effect on ecosystems, which can only be anticipated by air monitoring.

Dr. Brent Auvermann, a Texas AgriLife Research agricultural engineer, carried out the research.

According to Auvermann, all ecosystems receive some atmospheric inputs, such as nitrogen, phosphorus and sulfur.

The plant and animal life dominant to that region thrives because it has adapted to a particular rate of those nutrients.

"When the nutrient load changes, it can change the competitive ability of a species and allow different ones to thrive where they once were not competitive," said Auvermann.

The effects extend from major animal life such as deer down to the smallest bacteria.

For instance, scientists know that the Rocky Mountain National Park has been home to wildflowers for many years. But evidence from the last 20 years suggests that the ecosystem seems to be changing, with the wildflowers gradually being replaced by grasses and sedges.

Another change the Colorado scientists are noticing is acidification of the normally alkaline soils on the eastern side of the Continental Divide, which can lead to changes in the surface water and streams.

"Scientists believe the emissions from around eastern Colorado and the bordering states have resulted in detectable changes in the high alpine ecosystems," said Auvermann.

Auvermann joined a network of scientists monitoring such emissions about a year ago when his research team set up a monitoring site southeast of Canyon with wet and dry deposition measuring equipment.

Deposition is the process in which particles or gases in the air settle to the ground, vegetation or water surfaces.

The wet proportion is that which happens as a result of precipitation and its scrubbing effect.

While they are two separate projects, by measuring both in the same location, scientists can measure the total deposition.

"We're looking for long-term trends and whether they are increasing or decreasing," said Auvermann. "Wet deposition increases in wet years and decreases during a drought, so we have to take a longer-term view," he added.

The site located along the rim of Ceta Canyon is free from influence of any single source of air pollution.

The wet measurements can include ammonia, nitrate, calcium, sodium, potassium, phosphorus, sulfur and the acidity of rain or snow.

According to Auvermann, the major nutrients of concern are nitrogen and sulfur.

Based on the first year of monitoring data, the total deposition of inorganic nitrogen - ammonia plus nitrate - is between 3.5 or 4.5 pounds of nitrogen per acre per year.